Response of plant and microbial phytase on blood characteristics and egg quality traits in laying hens
PRAMOD K. TYAGI, PRAVEEN K.TYAGI,
S.V.S.VERMA AND K.B.SINGH*
Central Avian Research Institute, Izatnagar – 243 122
*Department of Animal Science, MJPRohilkhandUniversity, Bareilly- 243006
A 98 days feeding trial was conducted to examine the comparative effectiveness of plant and commercial microbial phytase with or without cholecalciferol on blood characteristics and egg quality traits in White Leghorn laying hens. 48 laying hens were distributed into 8 groups of 6 birds each. A standard corn-soy based diet was formulated and served as a control. Additional seven test diets were formulated in which about 50% of corn was replaced by phytase rich ingredients (i.e. wheat, wheat bran and barley). The control diet contained DCP with a 0.75% total phosporus and 0.25% phytate phosphorous, whereas rest of the seven diets were devoid of DCP and contained 0.45% total phosphorus and 0.29%.phytate phosphorous. Commercial microbial phytase was added in test diets D 3 and D 4 @ 250 and 500 FTU/kg of diet, whereas in diet D 5 and D 6 1-25 dihydroxycholicalciferol were added @ of 600 and 1200 ICU/kg. Diets D 7 and D 8 contained both microbial phytase and 1-25 dihydroxycholicalciferol @ of 250 FTU/600 ICU and 500 FTU/ 1200 ICU per kg. All diets were formulated to be isocaloric and isonitrogenous. Fifteen eggs per dietary group laid by hens on the last three days in the 5 th, 10 th & 14 th wks of the feeding period (15x8x3=366) were utilized for egg quality traits. At the end of experiment, representative blood samples were collected from each dietary treatment and were analyzed for blood calcium and serum inorganic phosphorus contents. The results revealed no significant differences for egg quality characteristics in terms of egg weight, shape index, shell thickness, shell weight, albumin index and yolk index. Supplementation of cholecalciferol @ 600 ICU/kg in diet increased (P<0.05) serum inorganic phosphorus level, however, supplemental microbial phytase at both the levels did not improve the serum inorganic phosphorus level in laying birds. No difference was found on blood calcium level. It may be concluded that inclusion of phytase rich ingredients such as wheat, wheat bran and barley in layer diet (devoid of inorganic phosphorus supplement) improved the phytate phosporus utilization without affecting the egg /shell quality traits.